When and who
The main ONE Pass holder or an EA acting for the holder cancels when the dependant no longer intends to stay in Singapore. The detailed rule is within the week before departure. A separate cancellation is unnecessary when the dependant becomes a PR or the main ONE Pass is cancelled: family passes cancel automatically with it and cannot be reinstated. The DP page gives 10 February departure with requests from 3 February. Its introductory sentence says “within 1 week of” departure, but the detailed table specifies before departure.
How to cancel and remain lawfully until departure
Use EP eService through myMOM Portal; cancellation is immediate. If the dependant is still in Singapore, request STVP for up to 89 days from application. MOM emails it to the requestor, main holder and dependant. Show STVP with a valid passport on departure. Leave before STVP expiry; destroy the cancelled card by cutting it in half and discarding it. Related LOC or WP also cancels when DP cancels.
Official source
Written independently from official MOM source material.